This application claims priority under 35 U.S.C. xc2xa7xc2xa7119 and/or 365 to Patent Application No. 0003462-9 filed in Sweden on Sep. 28, 2000.
The present invention relates to a tool for chip removing machining, said tool comprising a drill and a countersinker mounted thereto. The countersinker has at least one cutting insert for chip removing machining. The drill is provided with at least one chip flute which extends in the axial direction of the drill. The invention also relates to a countersinker, per se.
Through U.S. Pat. No. 3,575,520 is previously known a tool comprising a drill on which a countersinker is provided. The countersinker has an internal hole and a radial slot that extends from the internal hole to the external peripheral surface. The diameter of the internal hole of the countersinker conforms in principle to the external diameter of the drill. The radial slot allows the internal diameter of the countersinker to be somewhat widened, which in turn allows the countersinker to be pushed onto the drill in its axial direction. The countersinker is fixed on the drill by a screw in the area of the radial slot clamping the countersinker around the drill, i.e. the countersinker is fixed relative to the drill by means of friction between the internal hole of the countersinker and the peripheral surface of the drill.
Through U.S. Pat. No. 3,635,573 is also known a tool comprising a drill on which a countersinker is provided. The countersinker has an internal hole, which has a diameter that is somewhat larger than the external diameter of the drill. This means that the countersinker can be mounted on the drill by pushing it on the drill in its axial direction. Fixation of the countersinker, relative to the drill, is made through a substantially radially directed screw that extends through the wall of the countersinker and is received at its free end within a chip flute of the drill. Thereby the countersinker is fixed relative to the drill both in axial and circumferential directions.
A general problem of the above described countersinkers is that since the internal hole of each countersinker is circular and the drill is provided with a number chip flutes, spaces will be formed between the internal bore wall of the countersinker and the chip flutes, such that chips will frequently get stuck in said spaces. This leads to chip stoppage.
Sweden Patent No. 62052 discloses a one-piece countersinker held to the drill by means of a screw. The known countersinker needs bushings to remain in the wanted axial position.
A primary object of the present invention is to provide a tool and a countersinker of the above-captioned type, wherein the tool carrying the countersinker, does not, to the utmost possible extent, lead to chip stoppage.
Still another object of the present invention is to provide a tool where driving of the countersinker will depend on an interference contact between co-operative surfaces, and not through friction.
Still another object of the present invention is to provide a tool where cutting inserts of the countersinker will obtain an exact positioning in the axial and circumferential directions of the drill.
Still another object of the present invention is to provide a tool where the countersinker shall have a relatively low weight.
The invention pertains to a tool for chip removing machining. The tool comprises a drill and a countersinker mounted thereto. The countersinker has at least one insert seat for receiving a cutting insert. The drill defines an axis of rotation and is provided with at least one chip flute extending in a generally axial direction of the drill. The countersinker includes a connection portion received in the chip flute and configured with a shape generally corresponding to that of the chip flute, so as to be form-locked therein. Preferably, the connection portion defines a section of a wall of a chip-removal channel defined by the chip flute.